I have seen a Hella/Volvo concept with gas tubes running the length of the lights, like the old Lincoln Mark 8 came with. It was cool, but no doubt expensive.

VOlvo didn't light up the upper part in the early 90s because LEDs were too expensive and using bulbs in the area would probably cause melting due to the lack of air space and resulting poor heat transfer.

I think it's possible to do what you want, I would get a second set off ebay to fiddle with. Since LEDs use much less energy, the additional drain "should" not have a negative effect.

As for the spoiler, there are aftermarket CHMSLs out there, try googling for them.

Please post how it turns out, you may have a cottage industry starting up!